I’ve always felt a bit uncomfortable about the idea of someone switching to a smaller blade size, if they can’t achieve a desired stroke-rate with their current paddle (due to a ‘high load’). Switching to a smaller blade (same overall paddle length) reduces the ‘load’ felt by the paddler, as the smaller blade slips more in the water. But this seems a bit like ‘slipping’ the clutch in a car, a temporary expedient to ‘keep the revs up’, but perhaps not the right substitute for being in the right gear! (The right ‘gear’ might be better achieved by shortening the paddle shaft).
After many years of relying on this intuitive approach to choice of blade size, I’m now comfortable it was correct, supported by the results indicated with applying Newtonian physics, maths, and a practical experiment.